<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>外边距合并&塌陷</title>
		<style type="text/css">
			* {
				margin: 0;
				padding: 0;
			}
			.top,.foot {
				width: 200px;
				height: 200px;
			}
			.top {
				background-color: #FFC0CB;
				margin-bottom: 3.125rem;
			}
			.foot {
				background-color: #FF8400;
				margin-top: 1.25rem;
			}
			.father {
				width: 500px;
				height: 500px;
				/* padding: 3.125rem; */
				background-color: #FF6700;
				overflow: hidden;
			}
			.son {
				width: 12.5rem;
				height: 200px;
				background-color: #008000;
				margin-top: 1.25rem;
			}
		</style>
	</head>
	<body>
		<div class="top"></div>
		<div class="foot"></div>
		<hr>
		<h1>塌陷</h1>
		<div class="father"><div class="son"></div></div>
		
	</body>
</html>
